THE CROW AND ITS RELATION TO MAN. 69 



wild fruits, as sumac, poison ivy, poison oak, bayberry, dogwood, 

 sour gum, cherry, and juniper, ceases when the soft outer portion has 

 been utilized. To aid even in this process of digestion crows swallow 

 large quantities of sand, gravel, shell fragments, or anything else 

 that will serve as a grinding medium. After a large number of such 

 seeds have been eaten and the digestible portions assimilated, the 

 remains are regurgitated. The fact that embryos of these seeds are 

 seldom affected by this process, and that a large part of those dis- 

 gorged are capable of germination, brings up the important problem 

 of seed distribution. 



The material so disgorged usually assumes an ellipsoid or spheri- 

 cal form, but is quite variable in size (PI. II, fig. 1). These masses, 

 commonly called pellets, as in the case of similar ejecta of birds of 

 prey, are found in great abundance at crow roosts, and wherever a 

 place has been occupied by these birds for several successive winters 

 a substantial growth of their common food plants usually springs up. 



An idea of the number of seeds deposited at one of these roosts 

 may be gained from the following description given by Prof. 

 Barrows: 1 



The following facts serve to show how extensive is this seed planting by 

 crows in the vicinity of the winter roosts : On February 8, 1889, I visited the 

 well-known — almost historical — crow roost located on the Virginia side of the 

 Potomac River just opposite Washington, D. C. The exact location of this roost 

 varies from time to time, but at the date mentioned it was entirely within the 

 grounds of the National Cemetery at Arlington, and covered an area of 12 or 15 

 acres of second-growth deciduous trees. The ground beneath these trees was 

 pretty evenly covered with the ejecta of the crows, forming a deposit which in 

 places was an inch or more thick, though the average deposit was probably 

 rather less than half an inch. A representative spot free from underbrush was 

 selected, and all the material above the leaves from an area 2 feet square was 

 carefully collected, dried, and examined. The weight of this material when dry 

 was almost exactly 1 pound, and it contained (aside from gravel, bits of bone, 

 shell, corn hulls, and some excrement) the following seeds: 



Poison ivy (Rhus toxicodendron) 1,041 



Poison sumac (Rhus venenata) 341 



Other sumacs (Rhus) 3,271 



Juniper or red cedar (Juniperus virginiana) , 95 



Flowering dogwood (Cornus florida) 10 



Sour gum (Nyssa sylvatica) 6 



Total 4, 764 



A little calculation shows that the roost of 15 acres must have contained 

 upward of 778,000,000 seeds, or more than enough to plant 1,150 acres as 

 thickly as wheat is sown. 



A series of nine pellets, gathered at a former roost near St. Louis, 

 Mo., and examined by the writer, contained an average of 36 poison- 



1 Barrows, W. B., The Common Crow of the United States : Bull. 6, Div. of Ornith. and 

 Mamm., U. S. Dept. Agr., pp. 23-24, 1895. 



